FEL Workshop 8-10 March 2005 LASER PROCESSING LABORATORY Michel Meunier Canada Research Chair Department of Engineering Physics École Polytechnique de Montreal http://LPL.phys.polymtl.ca
FEL Workshop 8-10 March 2005
LASER PROCESSING LABORATORY
Michel MeunierCanada Research Chair
Department of Engineering PhysicsÉcole Polytechnique de Montreal
http://LPL.phys.polymtl.ca
FEL Workshop 8-10 March 2005
LPL’s Research activitiesMission:
Develop and model new laser material processes for: microelectronics, nanotechnologies, biotechnologies, photonics and MEMS
Laser-materials interaction:Theory and simulation of laser-materials interaction
Laser microengineering of materials :Laser trimming of microelectronics circuits (LTRIM process); Femtosecond laser micromachining.3D laser micromachining of photosensitive glasses3D laser fabrication of photonics components
Laser nanoengineering of materials:Laser fabrication of nanostructured thin films, nanoparticles and nanotubes. Applications to biosensing and nanobiophotonique
Personnel: ~201 Professor, 1 senior researcher, 3 research associates, 12 graduate students and 4 undergraduate students.
FEL Workshop 8-10 March 2005
Colloidal metal nanoparticles synthesized by femtosecond laser
ablation in liquids
M. Meunier, A. V. Kabashin, J.-P. Sylvestre, S. Besner,
F. Winnik and E. SacherLaser Processing Laboratory,
École Polytechnique, Montréal, Canada
FEL Workshop 8-10 March 2005
Content
ColloidsWhys laser ablation?Why femtosecond laser ablation?Mechanism of femtosecond laser ablation in liquids
and formation of nanoparticlesChemistry of gold nanoparticles in water, KCl, NaOH,
Cyclodextrin and DextranConclusionUse of FEL?
FEL Workshop 8-10 March 2005
Colloidal Gold NanoparticlesAbsorption spectra: Surface plasmon resonance (520 nm)
Biosensing and pharmacology applicationsAntibodies are detected by a change of optical
characteristics of gold nanoparticles
Desired characteristics of nanoparticles:- Small (< 30 nm), with narrow size distribution- Availability of reactive chemical groups for further
attachment to biomolecules
Conventional chemical fabrication methodReduction of chloroauric acid (HAuCl4) with citrate in water
Control size by adding a stabilizing agent (thiol- (-SH) containing molecules.)
Disadvantages: Contamination (impurities; Cl on surface, …)
FEL Workshop 8-10 March 2005
Why laser ablation of solids in liquids ?
Laser ablation in vacuum leads to highly energetic species and particles
Laser ablation in neutral gas (few Torrs) results in the cooling of speciesand formation of “cold” nanoclusters
Laser ablation in liquids:Rapid quench of hot species and formation of
cold nanoclustersDirect formation of colloidal solution
- Biosensor - Spin-on
FEL Workshop 8-10 March 2005
“Long” pulse laser ablation in liquidsIn distilled water:~5-200 nm particles with broad size distribution Reasons:- Ablation is mainly due to shock wave - Post-ablation: large quantity of ‘low’ but sufficient energetic particles thatcoalesce to form large particles
ns fsTransmitted energy (%) Few % 20-45
Mechanical energy (%) ~80% 15 %
In surfactants:Surfactant (sodium dodecyl sulfate or SDS) covers someablated particles, thus limiting coalescence (big particles) and aggregation.
Disadvantages: - SDS terminates gold surface makingit hardly useful for bioimmobilizations
- SDS is not biocompatible (denaturation of proteins)
Exemple: Nd:YAG laser (1064 nm, 532 nm) with SDS
5-10 nm Au particles (size dispersion - 5 nm)
FEL Workshop 8-10 March 2005
Metal colloids in aqueous mediaAuthors Laser Materials Aqueous
mediaSize distributions Comments
Henglein(1993)
Rubis, 694 nm Au, Ni and C
Pure H2O
Pure H2O
Pure H2O, NaCl, phtalazinePure H2O, SDS, CTABSDS
Pure H2O
Pure H2O
Tsuji (2002), (2003)
- Nd:YAG, 1064, 532 and 355 nm (ns)- Ti:saphire, 800 nm, 120 fs
Ag Pure H2O, 5-160 nm for ns5-90 nm for fs
Size dispersion of particles is reduced using femtosecond laser
Pure H2O,
CDs
2-4 nm for Au Ablation of thin films (few nm)
Cotton (1993) Nd:YAG, 1064 nm Ag, Au, Pt, Pd and Cu
10-50 nm for Ag Sound during ablation
Stepanek(1997), (1998)
Nd:YAG, 1064 nm, 20ns and 40 ps
Ag 6-140 nm for ns6-80 nm for ps
Size reduction effect of Cl- and adsorbing molecules (pht)
Yeh (1998), (2002)
Nd:YAG, 1064 and 532 nm Ag 4-120 nm Size reduction effect of surfactants (2002)
Kondow(2000),(2001),(2002), (2003)
Nd:YAG, 1064 and 532 nm Au, Ag and Pt
5-50 nm Size reduction effect of surfactants
Shafeev(2001), (2002)
Cu vapor laser, 511 nm, 20 ns
Ag, Au, Ti and Si
20-200 nm for Au and Ag
Partial oxidation of Ti and Si prepared in water
Compagnini(2002)
Nd:YAG, 532 nm Ag and Au 10-30 nm for Ag and Au
Kabashin JCPB, JAP (2003), SylvestreJACS (2004)
- Ti:saphire, 800 nm, 120 fs Au, Ag 3.5 ± 1nm for Au at small fluences2.5± 1 nm for Au in CDs at high fluence
Size of particles is dependant of laser fluence, CDs reduces particles size
FEL Workshop 8-10 March 2005
Experimental setup
Femtosecond laser:110 fs FWHM, 800 nm, 1 kHz
Aqueous solutions:
1. Pure water
2. Cyclodextrins (α-CD, β-CD and γ-CD) (Biologically compatible glucose-containing compounds)
3. Molecules containing an amine group (-NH2)
Focused laser radiation
Material to beablated
Liquid environment
A.V. Kabashin, M. Meunier, C. Kingston and J. H.T. Luong « Fabrication and Characterization of Gold Nanoparticles by Femtosecond Laser Ablation in Aqueous Solution of Cyclodextrins » J. Phys. Chem. B, 107, 4527-4531 (2003)
FEL Workshop 8-10 March 2005
fs laser ablation in water: fluence effects
F = 30 J/cm2
0 2 4 6 8 100
200
400
600
800
1000
Rel
ativ
e A
bund
ance
(arb
. uni
ts)
Particle Size (nm)
Ablation threshold:~5 J/cm23.5 ± 1 nm
FEL Workshop 8-10 March 2005
fs laser ablation in water: fluence effects
0 50 100 150 200 250 3000
200
400
600
800
1000
Rel
ativ
e ab
unda
nce
(arb
. uni
ts)
Particle size (nm)0 10 20 30 40 50 60 70 80 90 100
0
200
400
600
800
1000
Rel
ativ
e Ab
unda
nce
(arb
. uni
ts)
Particle Size (nm)
F = 1000 J/cm2 F = 160 J/cm2
- Diameter increases with fluence
- For intermediate fluences, size distributions can be fitted by two Gaussian functions
- Evidence for two different mechanisms of nanoparticle production
FEL Workshop 8-10 March 2005
fs laser ablation in water: fluence effects
200 400 600 800 1000
20
40
60
80
100
120
140
broad distribution
Narrow distributionMea
n P
artic
le S
ize
(nm
)
Fluence (J/cm2)
0 200 400 600 800 10000
20
40
60
80
100
broad distribution
narrow distribution
Siz
e D
ispe
rsio
n at
FW
HM
(nm
)
Fluence (J/cm2)
Mean particle size Size Dispersion
Two size distributions are present Two different mechanisms of particle formation
Kabashin and Meunier « Properties of femtosecond laser ablation in liquidenvironment and formation of gold nanoparticles» J. Appl. Phys., 94, 7941 (2003)
FEL Workshop 8-10 March 2005
200 J/cm2
30 J/cm2
- Molten layer - Optical breakdown of the water above the gold substrate leading to hot plasma generation and mechanical effect (cavitation bubble, shock wave) affecting the surface.
fs laser ablation in water: craters on gold after femtosecond ablation in water (5000 pulses)
FEL Workshop 8-10 March 2005
Experimental setup
A sound is generated due to generation of shock wave and collapse of cavitation bubble
Optical breakdown of the liquid
Sound can be recorded by a microphone connected to a computer tobetter control the production of particles
target
liquid
laserradiation
FEL Workshop 8-10 March 2005
Mass lossMass loss of gold substrate and sound intensity vs. position of focal plane relatively to the surface target
-1000 -500 0 500 1000 1500 2000 2500 3000-0,2
0,0
0,2
0,4
0,6
0,8
1,0
1,2
Soun
d in
tens
ity (A
.U.)
Position of focal plane relative to the surface (microns)
-1000 -500 0 500 1000 1500 2000 2500 3000
0,0
0,1
0,2
0,3
0,4
0,5
0,6
Mas
s Lo
ss (m
g)
Mass loss is maximal when sound intensity is maximal
Indication for ablation mechanism related to optical breakdowneffects
0.35 mJ/pulse,
20 min, rotation of target
x
H2O
Au
FEL Workshop 8-10 March 2005
Optical ExtinctionOptical extinction of Au colloids vs. position of focal plane relatively to the surface target
Focal positions away from the focal position generating maximal sound intensity results in less ablation and smaller particles
- Experimental conditions: 0.35 mJ/pulse, 5 min, rotation of target- Positions are relative to the point of maximal sound intensity
300 400 500 600 700 8000,01
0,1
1
2mm before
2mm after
1mm before
1mm after
Max sound
Extin
ctio
n (A
.U.)
Wavelenght (nm)
FEL Workshop 8-10 March 2005
Effect of focusing positionOptical breakdown
Sound maximum and ablation due tooptical breakdown of water maximumLarge nanoparticles and broad plasmon peak
Energy density decreases and optical breakdown effects (ablation + sound) decreases and disappears. Direct photon ablation, smaller nanoparticle and finer plasmon peak
Optical breakdown is to far from surface: ablation efficiency decreases. Few nanoparticles and plasmon peak disappears.
Further away
FEL Workshop 8-10 March 2005
fs laser ablation in water:mechanisms of particle formation
A) “Low” fluence B) “High” fluence
Direct fs laser ablation Direct
fs laser ablation
1) First few picoseconds
No other ablation mechanism when optical breakdown of water is avoided.
3) Fractions of a millisecond later
2) Micro- millisecond range
Cavitationbubble
boundary
Collapse of the cavitation bubble
optical breakdown of water = hot plasma generation
Vapor
-Ablation related to plasma or mechanical effects or both ???
Hot plasma
Conclusion:fs laser radiation at low fluences is unique in obtaining fine nanoparticles size
Narrow size distribution with mean particle size between 3.5 and 12 nm
Broad size distribution with mean particle size 20 – 120 nm
FEL Workshop 8-10 March 2005
Summary on mechanism• Two different mechanisms:
– «pure» laser ablation at «low» fluence: very fine small nanoparticles
– «optical breakdown» induced ablation at «high» fluence: large nanoparticles
• Few nm nanoparticles can be produced by fslaser ablation in WATER (impossible with ns lasers) (absence of any chemicals)
• Stability: For fine nanoparticles (5-7 nm) even after two years in water, no clustering is seen!
FEL Workshop 8-10 March 2005
Chemistry of gold nanoparticlesNanoparticles fabricated in deionized water
(substrat HOPG)
0
+1 et Au+3)
92 90 88 86 84 820
10000
20000
30000
40000
50000
60000
70000
Au4f5/2
+3
Au4f5/2
+1
Au4f5/2
0
Au4f7/2
+3
Au4f7/2
0
Au4f7/2
+1
Inte
nsity
(A.U
.)
Binding energy (eV)
XPS Au4f
- Nanoparticles are basicallycomposed of Au
- Nanoparticles are partiallyoxidized (Au
FEL Workshop 8-10 March 2005
Effect of OH- et Cl- ionsGold nanoparticles were produced under identical conditions
10 mM KClDeionized water NaOH pH 9.4
Size reduction when the ablation is performed in the presence of KCl and NaOH
Chemical interaction between Cl- and OH- with the gold surface
FEL Workshop 8-10 March 2005
Effect of OH- et Cl- ionsZeta potentiel measurements: surface charge of nanoparticles
Methodology: Mobility of particles prepared in 10 mM of NaCl was measured, while an electric potential was applied
Conclusions
- Particle surface exchanges protons (H+) with aqueous medium
- OH groups are responsible for the negative charge of nanoparticles
Au-OH ↔ Au-O- + H+2 3 4 5 6 7 8 9 10 11 12
-50
-45
-40
-35
-30
-25
-20Faster Au nanoparticleagglomeration
Zeta
pot
entia
l (m
V)
pH
Acid basic
FEL Workshop 8-10 March 2005
Effect of cyclodextrins
Chemistry: oligosaccharide cyclique containing 6, 7 et 8 alpha-D-glucoses forming a toroidal
Effect of α, β et γ-CD
J. Szejtli, Chem. Rev., 98, 1743 (1998)
0 5 10 15 200
200
400
600
800
1000
Rel
ativ
e A
bund
ance
(arb
. uni
ts)
Particle size (nm)
0.01 M β-CD 0.01M β-CD solution: 2.3 ± 1 nm
A.V. Kabashin, M. Meunier et.al,
J. Phys. Chem. B 107, 4527 (2003)
How do cyclodextrins react with gold?
FEL Workshop 8-10 March 2005
Conclusion• The size of nanoparticles can be controlled by changing conditions of ablation.
•Two different mechanisms: pure and optical breakdown ablation
• Fs laser ablation of Au in liquids:“Low” fluence in water: 3.5 ± 1 nm“High” fluence in water: > 20 nmIn Cyclodextrins 2.3 ± 1 nm
• The nanoparticles are mainly metallic, but their surface is partially oxidized
• It is possible to achieve interactions of gold nanoparticles during their formation in order to control the nanoparticle size and surface chemistry. Examples:
- Ions (OH- et Cl-)- Cyclodextrines- Dextran
• Fine QDs can be made
FEL Workshop 8-10 March 2005
References (M. Meunier)First
authorTitle Journal
J.-P. Sylvestre
Surface chemistry of gold nanoparticles produced by laser ablation in aqueous media
Phys. Chem. B. 108, 16864-16869 (2004)
J.-P. Sylvestre
Stabilization and Size Control of Gold Nanoparticles during Laser Ablation in Aqueous Cyclodextrins
J. Am.. Chem. Soc. 126, 7176-7177 (2004)
A. V. Kabashin
Synthesis of colloidal nanoparticles during femtosecond laser ablation of gold in water
J. Appl. Phys. 94, 7941-7943, (2003)
A. V. Kabashin
Fabrication and Characterization of Gold Nanoparticles by FemtosecondLaser Ablation in Aqueous Solution of Cyclodextrins
J. Phys. Chem. B, 107, 4527-4531 (2003)
J-P. Sylvestre
Femtosecond laser ablation of gold in water: influence of the laser-produced plasma on the nanoparticle size distribution
Applied Physics A. 80, 753-758 (2005)
WEB site of LPL http:// lpl.phys.polymtl.ca/